During the Call of Duty: Black Ops 4 beta, the game's multiplayer mode ran at a stable tickrate of 60Hz, which has now dropped to 20Hz at the game's launch - according to reports.
You may remember that during the Call of Duty: Black Ops 4 beta, the game's netcode was praised for hitting the crucial 60Hz send and receive tickrate. Blackout, on the other hand, maxed out at 20Hz.
Many hoped the release version would hopefully bring Blackout more in line with multiplayer, but the reverse is what seemingly happened. According to testing by Reddit user Smcro, backed by analysis from YouTuber Battle(non)sense - whom you may recognise from many of his netcode testing videos, the game's tickrate has dropped to just 20Hz in regular multiplayer.
This means both multiplayer and Blackout now run at the reduced 20Hz, which isn't ideal. Being a 60fps game - at least on consoles - Black Ops 4 would receive one update per frame when server tickrate is 60Hz. This drops to every third frame at a 20Hz tickrate.
Curiously, client send rate is able to reach 60Hz, but servers are mostly locked to 20Hz, with occasional spikes to 30Hz. This essentially makes it so the experience is near identical across Blackout, and multiplayer, but doesn't improve the experience.
Players certainly noticed the difference in the beta, and Treyarch may have decided to bring them both in line rather than work on upgrading Blackout's server tickrate, which likely requires a fair amount of work - if it's even possible.
For its part, Treyarch tried to assuage player concerns, though without responding directly to the criticisms.
"We’re constantly working to optimise the game, and particularly network performance, to ensure the highest quality online experience for our players. For a game launch with as massive a population as ours hitting so many global servers at once, we configure our infrastructure to ensure game stability as the highest priority over all other factors," Treyarch noted in an update.
"Now that we’re past the initial launch of the game, we are focusing on fine-tuning network performance around the globe, using the real-world data that we have collected. Over the course of the next two weeks, we will roll out several updates to our network setup that will continue to improve upon the experience of our players since launch."
This could indicate that the developer intends to upgrade the tickrate now that the launch day surge has died down, which would make sense. However, without constant testing on the part of players, we may never find out for sure.
For reference, Call of Duty: WW2 launched with a stable 60Hz server tickrate on all platforms, a feature that persists to this day.